This invention relates to cationic paint binders. More particularly, the invention relates to cationic paint binders based on modified epoxy resins which include urea groups which are water-dilutable upon protonation and which will internally crosslink at elevated temperatures.
Commonly assigned U.S. application Ser. No. 833,163 filed Feb. 27, 1986 discloses cationic compounds carrying urea groups obtained through reaction of beta-hydroxyamines, isocyanate compounds, and formaldehyde which function as substantially water-insoluble crosslinking components for cationic paint binders.
It has now been found that certain of the cationic compounds disclosed in U.S. application Ser. No. 833,163 can be modified to provide water-dilutable binders which have enhanced characteristics over commonly employed binders especially when used for cathodic electrodeposition. The cationic compounds useful as crosslinking components in cationic paint binders disclosed in U.S. application Ser. No. 833,163, subject to modification according to this invention, are the compounds obtained from beta-hydroxyamines having the formula-- ##STR2## wherein R.sub.1 is an alkyl radical or a hydroxyalkyl radical and R.sub.2 is an aliphatic and/or aromatic radical of a di- or polyglycidyl compound reacted with partially blocked polyisocyanates, and the subsequent reaction with formaldehyde with the separation of water.